private void readContinuationHeader() throws IOException {
int previousStreamId = streamId;
length = left = readMedium(source);
byte type = (byte) (source.readByte() & 0xff);
flags = (byte) (source.readByte() & 0xff);
if (logger.isLoggable(FINE)) logger.fine(formatHeader(true, streamId, length, type, flags));
streamId = (source.readInt() & 0x7fffffff);
if (type != TYPE_CONTINUATION) throw ioException("%s != TYPE_CONTINUATION", type);
if (streamId != previousStreamId) throw ioException("TYPE_CONTINUATION streamId changed");
}
private void readHeader() throws IOException {
if (closed) throw new IOException("closed");
int b0 = source.readByte() & 0xff;
opcode = b0 & B0_MASK_OPCODE;
isFinalFrame = (b0 & B0_FLAG_FIN) != 0;
isControlFrame = (b0 & OPCODE_FLAG_CONTROL) != 0;
// Control frames must be final frames (cannot contain continuations).
if (isControlFrame && !isFinalFrame) {
throw new ProtocolException("Control frames must be final.");
}
boolean reservedFlag1 = (b0 & B0_FLAG_RSV1) != 0;
boolean reservedFlag2 = (b0 & B0_FLAG_RSV2) != 0;
boolean reservedFlag3 = (b0 & B0_FLAG_RSV3) != 0;
if (reservedFlag1 || reservedFlag2 || reservedFlag3) {
// Reserved flags are for extensions which we currently do not support.
throw new ProtocolException("Reserved flags are unsupported.");
}
int b1 = source.readByte() & 0xff;
isMasked = (b1 & B1_FLAG_MASK) != 0;
if (isMasked == isClient) {
// Masked payloads must be read on the server. Unmasked payloads must be read on the client.
throw new ProtocolException("Client-sent frames must be masked. Server sent must not.");
}
// Get frame length, optionally reading from follow-up bytes if indicated by special values.
frameLength = b1 & B1_MASK_LENGTH;
if (frameLength == PAYLOAD_SHORT) {
frameLength = source.readShort() & 0xffffL; // Value is unsigned.
} else if (frameLength == PAYLOAD_LONG) {
frameLength = source.readLong();
if (frameLength < 0) {
throw new ProtocolException(
"Frame length 0x" + Long.toHexString(frameLength) + " > 0x7FFFFFFFFFFFFFFF");
}
}
frameBytesRead = 0;
if (isControlFrame && frameLength > PAYLOAD_BYTE_MAX) {
throw new ProtocolException("Control frame must be less than " + PAYLOAD_BYTE_MAX + "B.");
}
if (isMasked) {
// Read the masking key as bytes so that they can be used directly for unmasking.
source.readFully(maskKey);
}
}
private void readPriority(Handler handler, int streamId) throws IOException {
int w1 = source.readInt();
boolean exclusive = (w1 & 0x80000000) != 0;
int streamDependency = (w1 & 0x7fffffff);
int weight = (source.readByte() & 0xff) + 1;
handler.priority(streamId, streamDependency, weight, exclusive);
}
private void readPushPromise(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) {
throw ioException("PROTOCOL_ERROR: TYPE_PUSH_PROMISE streamId == 0");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
int promisedStreamId = source.readInt() & 0x7fffffff;
length -= 4; // account for above read.
length = lengthWithoutPadding(length, flags, padding);
List<Header> headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.pushPromise(streamId, promisedStreamId, headerBlock);
}
private void readData(Handler handler, int length, byte flags, int streamId)
throws IOException {
// TODO: checkState open or half-closed (local) or raise STREAM_CLOSED
boolean inFinished = (flags & FLAG_END_STREAM) != 0;
boolean gzipped = (flags & FLAG_COMPRESSED) != 0;
if (gzipped) {
throw ioException("PROTOCOL_ERROR: FLAG_COMPRESSED without SETTINGS_COMPRESS_DATA");
}
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
length = lengthWithoutPadding(length, flags, padding);
handler.data(inFinished, streamId, source, length);
source.skip(padding);
}
private void readHeaders(Handler handler, int length, byte flags, int streamId)
throws IOException {
if (streamId == 0) throw ioException("PROTOCOL_ERROR: TYPE_HEADERS streamId == 0");
boolean endStream = (flags & FLAG_END_STREAM) != 0;
short padding = (flags & FLAG_PADDED) != 0 ? (short) (source.readByte() & 0xff) : 0;
if ((flags & FLAG_PRIORITY) != 0) {
readPriority(handler, streamId);
length -= 5; // account for above read.
}
length = lengthWithoutPadding(length, flags, padding);
List<Header> headerBlock = readHeaderBlock(length, padding, flags, streamId);
handler.headers(false, endStream, streamId, -1, headerBlock, HeadersMode.HTTP_20_HEADERS);
}
private static int readMedium(BufferedSource source) throws IOException {
return (source.readByte() & 0xff) << 16
| (source.readByte() & 0xff) << 8
| (source.readByte() & 0xff);
}
@Override
public boolean nextFrame(Handler handler) throws IOException {
try {
source.require(9); // Frame header size
} catch (IOException e) {
return false; // This might be a normal socket close.
}
/* 0 1 2 3
* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | Length (24) |
* +---------------+---------------+---------------+
* | Type (8) | Flags (8) |
* +-+-+-----------+---------------+-------------------------------+
* |R| Stream Identifier (31) |
* +=+=============================================================+
* | Frame Payload (0...) ...
* +---------------------------------------------------------------+
*/
int length = readMedium(source);
if (length < 0 || length > INITIAL_MAX_FRAME_SIZE) {
throw ioException("FRAME_SIZE_ERROR: %s", length);
}
byte type = (byte) (source.readByte() & 0xff);
byte flags = (byte) (source.readByte() & 0xff);
int streamId = (source.readInt() & 0x7fffffff); // Ignore reserved bit.
if (logger.isLoggable(FINE)) logger.fine(formatHeader(true, streamId, length, type, flags));
switch (type) {
case TYPE_DATA:
readData(handler, length, flags, streamId);
break;
case TYPE_HEADERS:
readHeaders(handler, length, flags, streamId);
break;
case TYPE_PRIORITY:
readPriority(handler, length, flags, streamId);
break;
case TYPE_RST_STREAM:
readRstStream(handler, length, flags, streamId);
break;
case TYPE_SETTINGS:
readSettings(handler, length, flags, streamId);
break;
case TYPE_PUSH_PROMISE:
readPushPromise(handler, length, flags, streamId);
break;
case TYPE_PING:
readPing(handler, length, flags, streamId);
break;
case TYPE_GOAWAY:
readGoAway(handler, length, flags, streamId);
break;
case TYPE_WINDOW_UPDATE:
readWindowUpdate(handler, length, flags, streamId);
break;
default:
// Implementations MUST discard frames that have unknown or unsupported types.
source.skip(length);
}
return true;
}